Diabetes prevalence is related to age. One of the ways that age can be accounted for is age standardisation, a method of allowing comparisons between two or more populations with different age structures to remove age as a factor when examining correlations between other variables. For example, the age distribution of people with diabetes is heavily skewed towards the higher age groups (that is, older people are more likely to have diabetes than younger people). When looking at the labour force status of people with and without diabetes, it can be seen that people with diabetes are less likely to be in the work force, however, this could be due to the fact that there are more older people with diabetes and less older people in the work force. Age standardising removes age from the picture so it can be seen whether there is a correlation between diabetes and labour force status independent of age.

In this article, the Australian 2001 estimated resident population is used as the reference population.

BODY MASS INDEX (BMI)

This article uses measured height and weight data of persons from the 2007-08 NHS to calculate body mass index (BMI), a simple index of weight for height commonly used to classify people as underweight, normal weight, overweight and obese. It is defined as the weight in kilograms divided by the square of the height in metres (kg/m2).

In the 2007-08 NHS, people aged 15 years and over were asked questions about all exercise undertaken for fitness, recreation or sport (including walking for transport) in the week prior to the survey. They were then grouped into exercise levels (sedentary, low, moderate or high) based on a score derived from the frequency, duration and intensity of their physical activity in the previous week.

ALCOHOL CONSUMPTION

In the 2007-08 NHS, information was collected about a person's alcohol consumption for the three most recent drinking occasions in the week prior to the survey. This was averaged over 7 days and used to calculate levels of long term risk from alcohol consumption.

SOCIO-ECONOMIC INDEX FOR AREAS (SEIFA) INDEX OF DISADVANTAGE

From information collected in the Census of Population and Housing, the ABS has developed indexes to allow ranking of areas, providing a method of determining the level of social and economic wellbeing in that area. One of these indexes is the SEIFA Index of Relative Socio-economic Disadvantage, derived from attributes such as income, unemployment and educational attainment. In this article, people are grouped into quintiles ranking from areas of most disadvantage to those of least disadvantage, which enables comparisons to be made between the health characteristics of people living in each area.